Engineering method of analyzing the bearing capacity of horizontally loaded pile groups

An engineering method is presented for analysis of the bearing capacity of a horizontally loaded pile group on the basis of the resistance of a single pile with a free head; the method accounts for the interaction between piles in the foundation, and the rigid fixity of their heads in an undeformable grillage. Results of the analysis performed in accordance with the developed procedure are compared with data derived from field tests of pile foundations. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 7–11, March–April, 2000.     

Determination of loads on cantilevers of eccentrically loaded foundation slabs

Formulas for determining loads on cantilevers of eccentrically loaded foundations were obtained for the example of strip foundations. Cases of symmetric and asymmetric arrangement of the slabs relative to the wall blocks resting on these slabs are examined. A method is proposed for selecting slabs on the basis of bearing capacity with the use of Table 2 of State Standard 13580–85, which provides for only a symmetric arrangement of centrally loaded slabs. Recommendations on correcting the indicated GOST are given. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 14–16, July–August, 1994     

On some “generalizations” of analytical engineering methods

The studies of S. G. Bezvolev [1–3] are examined. Results of analyses performed by the procedure outlined in [1] are presented, and a soil model, which is based on this procedure [3], is discussed. In addition to this relation, the papers under consideration are also linked by the fact that they “generalize” the engineering methods proposed in [4, 5] for analysis of the settlements of slab and pile foundations. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 3, pp. 9–16, May–June, 2008.     

Strengthening beds and foundations during the rehabilitation of industrial structures on soils prone to caving

Experience with the strengthening of beds and foundations beneath structures on soils prone to caving in Ufa is described. Monolithic nonspliced pile foundations with a continuous reinforced-concrete slab are used, and their bearing capacity is determined and compared with computed values. As a result, the number of piles in the pile field was significantly reduced. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 23–25, November–December, 1994.     

Experimental investigations of pile loads and foundation settlements in tall large-panel buildings

Conclusions 1. During the process of settlement of pile foundations with and without gratings in the nine-story large-panel frameless buildings with transverse and longitudinal bearing walls, the loads were redistributed and equalized, which was a consequence of interaction between the relatively rigid building box and the pliant base of the foundation. 2. Field investigations of the actual pile loads in the foundations of the nine-story large-panel buildings made it possible to establish that the design pile loads exceeded the actual values by 12–16%. 3. The nature of the distribution of the forces in the elements of the pile foundations of the large-panel frameless buildings indicates the need for taking into account the pliancy of the soil base of the pile foundation and its joint operation with the constructional components of the building box for determining the pile loads and for designing the gratings as well as the wall panels with gratingless support. 4. In the pile foundations of the nine-story frameless large-panel buildings with load-bearing, frequently transverse walls of the type of Series 1-464D, with and without gratings on compressible soils, the loads in piles with equal rigidities of the soil bases can be assumed to act as uniformly distributed, as an approximation, in engineering analyses. In the case of different rigidities of the soil bases of the piles, the load on each pile can be determined as a force proportional to the corresponding rigidity. 5. The actual settlement of the pile foundation of the large-panel building on alluvial soils was greater by a factor of 5–6, and for the building on the clay soils of the Ufa floor it was greater by a factor of 15 in comparison with the settlement of a single pile constructed on the basis of the same static test results, under the same soil conditions, and for the same loads. Hence, the coefficient ζ recommended in the SNiP II-17-77 for transfer from settlements of individual piles in static tests to settlements of piles in foundations under long-term loading should be differentiated according to the soil type and state. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 8–10, March–April, 1982.     

Assigning dimensions of the footing of eccentrically loaded foundations

A procedure is suggested for determining the minimum dimensions for the footing of eccentrically loaded foundations with different shapes in plan, by graphoanalytic means. It is based on the functional relationship of static and structural parameters (vertical forces, moments of forces, shape of the foundations' footing, etc.), expressed in relative amounts, and can take into account the action of several combinations of loads in the calculation. The procedure is most effective in solving problems connected with designing the foundations of buildings (structures) to be reconstructed.Tomsk State Architectural and Construction Academy. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 10–13, September–October, 1993.     

Experience gained with the sinking of piles near existing building under soil conditions in lands along the Middle Ob'

Experience gained with pile driving near existing buildings in a accordance with the author's procedure, which takes into account conditions of the spread of elastic waves that develop in the ground during the driving of piles, and which does not cause soil deformations in the foundations beds of existing buildings, is presented. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 13–15, January–February, 2000.     

Stabilization of tubular pile foundations in heaving soils

Theoretical and experimental substantiation is provided for one of the mechanisms responsible for the frost heaving of tubular pile foundations. A method is proposed for its neutralization by suppressing convection of water in the recesses of the piles using aqueous solutions of polyvinyl alcohol. In many cases, the method makes it possible to dispense with use of seasonal cooling devices, and, in turn lower the cost of, and simplify the process of stabilizing tubular pile foundations in heaving soils. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 25–29, November–December, 2006.     

Installation procedure for in-situ melted-soil piles using a low-temperature plasma generator

A new method is proposed for the installation of pile foundations. An experimental system has been developed for the installation of a pile field at the construction site. Tests have indicated a high bearing capacity for the experimental pile foundation bed formed from melted soils. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 16–20, November–December, 1999.     

Efficiency analysis of building foundations from experience gained with mass construction

Results of multiyear field observations of settlements, and also the designs of foundations for a large group of buildings and structures are generalized and analyzed. A significant discrepancy is revealed between the computed strengths of the bed soils and the actual pressures against the lower surfaces of the foundations. It is established that the pile foundations of residential buildings in Saint Petersburg have a high factor of safety. Two-sided scatter is noted for the computed settlements of the foundations as compared with the actual settlements; this scatter has reached hundreds of percents in both directions. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 18–21, November–December, 1996.     

Experience with the use of hollow reinforced-concrete circular piles and pile shells and means of improving their effectiveness

Conclusions 1. Use of reinforced-concrete HCP and PS on many projects involving industrial and civil construction may significantly lower material consumption for the construction of foundations and labor outlays for their installation. 2. Methods that prevent crack formation in PS during their embedment and while in service have been developed and implemented for the broader practical implementation of substantially refined HCP and PS designs; a vibratory procedure (vibratory pile drivers, vibrating grab buckets), which ensures the embedment of hollow circular piles and pile shells to a depth of up to 40–50 m has been created. 3. For broader implementation of HCP and PS, it is necessary to adjust their manufacture at plants run by interested ministries, bringing its volume to 10–15% of the volume of prismatic shells; and, to tool the manufacturers' plants with the required production equipment, which will provide for the manufacture of high-quality HCP and PS. The solution of these problems may increase the efficiency of pile-foundation constructions, save metal, cement, mineral resources, and energy, and lower labor outlays required for their installation. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 2–4, July–August, 1989.     

Causes of structural deformations of an apartment building on weak foundations in Verkhnekamsk

The results of monitoring are analyzed to ascertain the causes of structural deformation and settlement nonuniformity of an apartment building on pile foundations. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 19–20, September–October, 1999.     

Design and construction of a ring foundation for a radio-television tower

Characteristic features of the design and construction of a metallic radio-television tower on pile foundations with a ring grillage under the complex geologic-engineering conditions of Samara are described. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 20–24, July–August, 2007.     

Mathematical modeling of the installation of pile foundations in a dense urban setting

Principles are proposed for the construction of constitutive relationships for the solution of problems of geomechanics under large deformations. Examples are cited for the numerical modeling of the installation of pile foundations in accordance with various procedures for soil conditions found in Saint Petersburg. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, Nos. 4–5, pp. 13–18, July–October, 1998.     

Investigation of the stress state of micropiles

Results are presented for monitoring of the stress state of micropiles installed to strengthen the foundations of an industrial building. It is recommended to correct the design of the reinforcing cage of a pile in conformity with its actual serviceability at various depths. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 9–12, September–October, 2008.     

Application of pile foundations with grillage in frost zone of heaving soils

Conclusions 1. The installation of piles and pile foundations leads to a reduction in the heaving of soil in the space around the pile, the smallest values of which are observed inside the pile group. 2. Frost heaving decreases and, consequently, the normal forces of frost heaving that act on the grillage diminish with decreasing distance between piles in the group. 3. During freezing, the layers of soil exhibit a complex mechanical trajectory. As the freezing zone approaches these layers, they are displaced downward, i.e., the process of compaction of the thawed soil occurs under the pressure induced by the frost heave, and upward displacement of the soil layers (heaving) is then observed after freezing. 4. As a result of the freeze-thaw cycle, the soil in the space around the pile is compacted under the frost-heave pressure. The proposed construction of precast-pile foundations with a grillage in the frost zone has demonstrated its own serviceability. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 6–8, March–April, 1991.     

Stress state of foundation beds from surface loads

Solutions of three-dimensional problems for semi-infinite (existing in the form of extent) uniform and triangular strip loads, a uniform load on one quarter of the boundary plane of a half space, and a uniformly loaded corner of a strip foundation, which define the stress state in the bed near the ends of the strips and the ends and corners of the foundations more precisely, are presented. These solutions make it possible to account more accurately for the influence exerted by these stresses on the settlement of neighboring foundations and structures, and calculate more accurately the settlements of open strip foundations. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 5–9, January–February, 1996.     

小变形下考虑摩擦效应的桩基水平承载分析方法

当前我国各类大型工程建设对桩基设计提出了更高的要求,桩基水平承载计算是一个突出问题。从传统水平受荷桩分析方法入手,推导考虑侧壁摩擦力的桩基水平承载挠曲微分方程,提出小变形下考虑摩擦效应的桩基水平承载计算方法(fm法)。编制相应的分析程序,通过算例验证方法的正确性和有效性。进一步比较传统m法与本文fm法的异同,并深入探讨尺寸效应对桩基水平承载的影响,可供工程参考。     

Comparison of procedures specified in the construction rules and regulations and Eurocode-7 for analysis of shallow foundation beds

Results of analysis of permissible loads on shallow foundations are compared on the basis of Russian and European Regulations. Note that use of the computed strength of a soil bed as the limiting allowable pressure on the lower surface of a foundation frequently results in unjustifiably high safety factors relative to stability. A conclusion is drawn concerning the expediency of bringing the design procedure specified for foundation beds in the Construction Rules and Regulations into conformity with the Eurocode-7 procedure. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 19–24, July–August, 2006.     

Improvement of methods of constructing pile foundations in permafrost soils

This article discusses peculiarities of constructing pile foundations in permafrost soils in different natural, technical, and economic conditions. Examples are given of the most efficient use of combined methods of setting ready-made and precast monolithic piles. Scientific Research Institute of Foundations and Underground Structures. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 28–30, July–August, 1994.